Please post what components you have and where do you have trouble overclocking the CPU so we can help.
EDIT: if you have no idea what voltages, cores and bios settings are don't bother posting and instruct yourself on Google what those are. When you hit a problem then ask for help.
I found this also: http://www.tomshardware.co.uk/forum/229618-11-overclock...
But it would be helpful to pest more specs about your system.